St. John's Co-Cathedral, situated on Triq San Gwann in Valletta, Malta, is one of the island's most renowned and historically significant landmarks. Built between 1573 and 1578 by the Knights of St. John, the cathedral stands as a testament to the grandeur and influence of the Order during Malta's early modern period.

The cathedral’s exterior, with its modest façade, belies the opulence found within. Upon entering, visitors are greeted by an extraordinary interior that exemplifies Baroque artistry. The cathedral’s lavish decoration includes intricate marble floors, ornate stuccoes, and a series of impressive artworks by the Italian artist Caravaggio. The cathedral's centerpiece is the richly adorned main altar, while its chapels are lavishly decorated with magnificent artworks and elaborate tombs of Knights of St. John.

What makes St. John’s Co-Cathedral unique is its historical and artistic significance. It was originally built as a church for the Knights of St. John, and it served as the Conventual Church of the Order. The cathedral is renowned for its stunning floor mosaics made of marble, which depict various Knights of St. John. It also houses one of Caravaggio’s masterpieces, "The Beheading of Saint John the Baptist," which is displayed in the oratory.

The best time to visit St. John's Co-Cathedral is during the weekdays, preferably in the morning or early afternoon to avoid large crowds. The cathedral is open daily, with entrance fees applicable. Visitors should be aware that the cathedral is often busy, especially during peak tourist season, so purchasing tickets in advance or arriving early can help avoid long lines.

An interesting fact about St. John’s Co-Cathedral is its role in the historical and cultural fabric of Malta. It was a pivotal site for the Knights of St. John and holds significant religious and historical importance. The cathedral has also been featured in various documentaries and historical programs that explore Malta’s rich heritage.

Additionally, the cathedral’s understated exterior contrasts sharply with the opulence inside, symbolizing the humility and grandeur of the Knights. The cathedral is also a UNESCO World Heritage Site, recognized for its historical and architectural value within the context of Valletta’s fortifications and urban plan.

In summary, St. John's Co-Cathedral is a must-visit destination in Valletta, offering a rich tapestry of Baroque art and historical significance. Its remarkable interior and historical connections make it a central piece of Malta’s cultural and religious heritage.